Abstract
Purpose
Acquired Chiari I malformation developing after cerebrospinal fluid (CSF) shunting is an intriguing late complication of CSF shunt surgery and not only raises questions as to its pathogenesis but also poses many queries about the possible adverse effects on the subsequent child development as well as on the indications and possibilities of surgical correction.
Materials and methods
We report a series of 17 patients with the neuroradiological evidence of an “acquired” Chiari type I malformation. These patients, 3 to 24 years (mean 11.3 years), had been treated previously with an extrathecal CSF shunt. The follow-up varied from 2 to 12 years (mean, 6).
Results
Neuroradiological investigation demonstrated a small posterior cranial fossa, small ventricles, markedly reduced periencephalic subarachnoid spaces, and thickening of the skull vault and base. The degree of tonsillar herniation did not correlate with clinical manifestations. All patients with severe clinical manifestations or with progressive worsening of neuroradiological findings were considered for surgical treatment. Decompressive supratentorial craniotomy seemed to fit with the purpose of enlarging the intracranial volume without the risk of aggravating the hindbrain herniation. An immediate relief of clinical manifestations was observed in all patients. Not surgically treated patients did not show any clinical or radiological modification during all the follow-up.
Conclusions
This study contributes to the understanding of the underlying pathogenetic mechanisms of acquired Chiari type 1 malformation in cases of long-lasting supratentorial CSF shunting and provides a base for planning the best management, whether conservative or surgical.
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References
Arnett BC (2004) Tonsillar ectopia and headaches. Neurol Clin 22:229–236
Caldarelli M, Di Rocco C (2004) Diagnosis of Chiari I malformation and related syringomyelia: radiological and neurophysiological studies. Childs Nerv Syst 20(5):332–335
Chumas PD, Kulkarni AV, Drake JM, Hoffman HJ, Humphreys RP, Rutka JT (1993) Lumboperitoneal shunting: a retrospective study in the pediatric population. Neurosurgery 32(3):376–383
Chumas PD, Armstrong DC, Drake JM, Kulkarni AV, Hoffman HJ, Humphreys RP, Rutka JT, Hendrick EB (1993) Tonsillar herniation: the rule rather than the exception after lumboperitoneal shunting in the pediatric population. J Neurosurg 78(4):568–573
Cinalli G, Spennato P, Sainte-Rose C, Arnaud E, Aliberti F, Brunelle F, Cianciulli E, Renier D (2005) Chiari malformation in craniosynostosis. Childs Nerv Syst 21(10):889–901
Di Rocco C, Tamburrini G (2003) Shunt dependency in shunted arachnoid cyst: a reason to avoid shunting. Pediatr Neurosurg 38(3):164
Di Rocco C, Tamburrini G, Caldarelli M, Velardi F, Santini P (2003) Prolonged ICP monitoring in Sylvian arachnoid cysts. Surg Neurol 60(3):211–218
Di Rocco C, Velardi F (2003) Acquired Chiari type I malformation managed by supratentorial cranial enlargement. Childs Nerv Syst 19(12):800–807
Hassounah MI, Rahm BE (1994) Hindbrain herniation: an unusual occurrence after shunting an intracranial arachnoid cyst. Case report. J Neurosurg 81(1):126–129
Hoffman HJ, Tucker WS (1976) Cephalocranial disproportion. A complication of the treatment of hydrocephalus in children. Childs Brain 2(3):167–176
Holly LT, Batzdorf U (2001) Management of cerebellar ptosis following craniovertebral decompression for Chiari I malformation. J Neurosurg 94(1):21–26
Johnston I, Jacobson E, Besser M (1998) The acquired Chiari malformation and syringomyelia following spinal CSF drainage: a study of incidence and management. Acta Neurochir (Wien) 140:417–427
Kim SK, Cho BK, Chung YN, Kim HS, Wang KC (2002) Shunt dependency in shunted arachnoid cyst: a reason to avoid shunting. Pediatr Neurosurg 37(4):178–185
Lazareff JA, Kelly J, Saito M (1998) Herniation of cerebellar tonsils following supratentorial shunt placement. Childs Nerv Syst 14:394–397
Loukas M, Noordeh N, Shoja MM, Pugh J, Oakes WJ, Tubbs RS (2008) Hans Chiari (1851–1916). Childs Nerv Syst 24(3):407–409 Mar
Mendonça R, Lima TT, Oppitz PP, Raupp SF (2006) Herniation of the cerebellar tonsils after suprasellar arachnoid cyst shunt: case report. Arq Neuropsiquiatr 64(2B):523–525
Nishikawa M, Sakamoto H, Hakuba A, Nakanishi N, Inoue Y (1997) Pathogenesis of Chiari malformation: a morphometric study of the posterior cranial fossa. J Neurosurg 86(1):40–47
Osuagwu FC, Lazareff JA, Rahman S, Bash S (2006) Chiari I anatomy after ventriculoperitoneal shunting: posterior fossa volumetric evaluation with MRI. Childs Nerv Syst 22(11):1451–1456
Payner TD, Prenger E, Berger TS, Crone KR (1994) Acquired Chiari malformations: incidence, diagnosis, and management. Neurosurgery 34(3):429–434
Rekate HL (2008) Shunt-related headaches: the slit ventricle syndromes. Childs Nerv Syst 24(4):423–430
Tamburrini G, Di Rocco C, Velardi F, Santini P (2004) Prolonged intracranial pressure (ICP) monitoring in non-traumatic pediatric neurosurgical diseases. Med Sci Monit 10(4):MT53–MT63
Tamburrini G, Caldarelli M, Massimi L, Santini P, Di Rocco C (2005) Intracranial pressure monitoring in children with single suture and complex craniosynostosis: a review. Childs Nerv Syst 21(10):913–921
Tubbs RS, Law C, Oakes WJ, Grabb PA (2004) Acquired Chiari I malformation following baclofen pump placement in a child. Case report. J Neurosurg 101(2 Suppl):211–3
Acknowledgement
This study was supported by the Association “Ali di Scorta onlus, per la lotta alle malformazioni e ai tumori cerebrali infantili”, www.alidiscorta.it.
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Caldarelli, M., Novegno, F. & Di Rocco, C. A late complication of CSF shunting: acquired Chiari I malformation. Childs Nerv Syst 25, 443–452 (2009). https://doi.org/10.1007/s00381-008-0760-z
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DOI: https://doi.org/10.1007/s00381-008-0760-z